Age and Ageing

For a shorter life span of male sperm genes are responsible, according to a new study

A team of Japanese experts carried out an experiment on mice and found that a combination of genome copies created two females - bi-maternal or dvomajcinski (BM) - live an average of 186 days longer than those who were conceived by the usual combination of male and female genomes. The expected lifespan of mice used in the study is 600-700 days, which means that the BM mice lived for about 30 percent longer than ordinary. Lead researcher Professor Tomohiro Kono, Department of Biological Sciences, Faculty of Agriculture in Tokyo, said that for some time known that women live longer in almost all countries of the world and that this difference is recorded and "in almost all mammals." - However, till now not been known to cause these differences, in particular, it was not clear whether life span is regulated in mammals, the genome of one or both parents, said Kono. To find an answer to this question experts have created mice without using sperm. They collected eggs one-day females, genes prompted them to behave like genes of sperm and then implanted into the material developed neoplodene oocytes of adult mice from which they removed the nucleus. Thus generated cells began to develop into embryos that are ultimately usadene in uterine surrogate mothers. Birth to the BM mice with genetic material from two mothers and no father. At the same time, this is the usual fertilization created a control group of mice who had the same genetic material as well as BM mice, however, with the genes of the females and males. Then, from October 2005. by March 2006. track the development of 13 BM and 13 control mice and found that on average dvomajcinski lived 186 days longer. Interestingly, the long-lived mice were also significantly lighter than ordinary, and that they had a better immune system. All are grown in exactly the same conditions. Scientists believe that for this difference in duration of life is responsible Rasgrf1 expression of genes on chromosome number 9 that is associated with growth. - Our results are consistent with models based on sex selection of reproductive strategies. In other words, males maximize the ability to invest heavily in reproduction by increasing the body to get the opportunity for fertilization, which in turn shortens their lifespan. On the other hand, in females was not recorded such wasteful behavior. Rather they optimize their reproductive behavior of energy saving for childbirth, caring for offspring and avoiding enemies - explained in the journal Human Reproduction.